The present invention relates to an apparatus and method for stuffer crimping synthetic filament yarns.
EP-189099-B discloses a known texturizing nozzle wherein the portion of the yarn duct which is located downstream of an initial nozzle portion, and where the yarn is advanced with the pressurized fluid, is constructed with a cylindrical, in particular circular-cylindrical cross section and with a diameter which is constant over its length.
The known texturing nozzle as described above has proven to be effective, particularly in machines for carrying out a continuous spin-draw-texturing process, and it is very successfully employed by the industry for stuffer box crimping synthetic filament yarns of polyester, in particular polyethylene terephthalate, PA6, PA6.6, or PP at draw speeds downstream of the spinning stage ranging from 1800 to 3000 m/min. At this speed, however, a limit of the production speed is reached, inasmuch as the yarn tension in the filament bundle which is advanced by the nozzle, and any slackening of the yarn, lead to the formation of laps on the draw rolls and to instabilities in the production process.
It is accordingly the object of the present invention to improve the construction of the apparatus for stuffer crimping, so that the specified technical upper speed limit for a reliable performance of the stuffer box crimping by the known continuous spin-draw-texturing method may be further increased and wherein at the increased yarn speed, the nozzle still exerts an adequate tension on the advancing yarn.
It is a further object of the present invention to provide an apparatus and method for stuffer crimping having an increased speed capability, and wherein the high quality of prior systems as regards yarn crimping, consistency and disentanglement of the yarn plug, remains unchanged, and that the consumption and pressure of the pressurized fluid are as low and as economical as possible.